Seeing out a scrappy affair in the first leg, both sides will be hoping things improve on their way to Zagreb for Tuesday's second leg, where we'll find out which of these sides makes their way to the finals in Brazil.

With not too many positives to work from, Friday gave both teams a raft of items to contemplate before taking centre stage once again.

Iceland: Trust In One Up Top

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Sigthorsson

It's a terrible blow for Iceland that striker KolbeinnSigthorsson, who's been one of the club's most reliable attacking assets in qualification thus far, should have got injured on Friday night.

The forward was stretchered off on the stroke of half-time and replaced by EidurGudjohnsen, as Philip O'Connor confirmed on Twitter:

Sigthorsson off injured, giving 35-year-old Gudjohnsen a chance to be the hero. =) #WC2014#ICECRO

Sigthorsson will be a big miss for the Icelandic visitors on Tuesday, should he indeed fail to recover from the ankle injury in time. That being the case, Lars Lagerback shouldn't try to replace his man in another 4-4-2 line-up should Sigthorsson indeed be unfit.

Instead, it should be accepted that his side are bound to see less of the ball in Zagreb and a more packed midfield will be needed to break up Croatia's hold over the ball.

In that eventuality, Alfred Finnbogason would be the man to lead Iceland's line independently, although it will require some mighty support in order to make a go of things in attack.

Croatia: Expanding Horizons

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Only in the second period of Friday's encounter did Croatia begin to play a more expansive game and really develop a foothold in possession.

Up until then, the visitors seemed content to soak up any and all pressure but became the ones piling it on when they chose to, giving the likes of Mario Mandzukic and IvicaOlic more to work from.

It's vital that Tuesday's hosts pick up where they left off next week, taking to the pitch with the same tempo that let to Skulason being sent off last time out.